Mortality in US veterans with pulmonary hypertension: a retrospective analysis of survival by subtype and baseline factors

Abstract

Pulmonary hypertension (PH) occurs when the pulmonary vasculature is itself diseased or becomes affected secondarily by comorbid conditions, commonly left heart or lung disease. The high prevalence of chronic cardiopulmonary conditions among patients served by Veterans Health Administration (VHA) suggests this population may be particularly susceptible to PH. We sought to identify clinical features and outcomes in veterans diagnosed with PH. We utilized the VHA Corporate Data Warehouse to identify veterans diagnosed between January 1, 2003 and September 30, 2015, assess relevant patient characteristics and their survival time. The effects of PH subtype and baseline factors on outcome were estimated by Cox modeling. There were 110,564 veterans diagnosed with PH during the study period. These veterans were predominantly male, had median age 70.2, and had a high burden of comorbid conditions. PH was frequently due to left heart and/or lung disease. Average survival after PH diagnosis was 3.88 years. Compared with other types, PH due to left heart disease, lung disease or both had shorter survival. This large retrospective study of veterans demonstrates the significance of PH due to left heart and/or lung disease which was common and had high risk of death. Multi-comorbidity was common and added to risk. These findings underscore the need for risk assessment tools for subjects with non-Group 1 PH and novel management strategies to improve their outcome. This study details the largest retrospective cohort assembled for evaluation of secondary PH and allows hypothesis-generating inquiries into these common conditions that are rarely prospectively studied.

Keywords: comorbidity; pulmonary hypertension; retrospective cohort study; risk factors; survival.

Fig. 1.

Flow diagram for cohort development. Cohort generation query was performed 09/08/2017. Note that if a subject had the diagnosis code used as an outpatient only and for a duration <30 days, the diagnosis code use was considered a “Rule Out” use and the subject was excluded (see reference 19). CDW: corporate data warehouse; ICD-9: International Classification of Diseases 9th version; PH: pulmonary hypertension.

Fig. 2.

Kaplan–Meier survival curve for veterans with pulmonary hypertension receiving care in the Veteran Health Administration system, 01/01/2003-09/30/2015. (a) Overall survival. Median overall survival after diagnosis of PH is 3.88 years. (b) Overall survival stratified by gender. Median survival for females is 7.05 years compared with 3.81 years for males. (c) Overall survival stratified by PH subtype. There is lower survival in those with PH due to left heart disease (Group 2), lung disease (Group 3) and multiple causes, when compared with patients with presumed Group 1 PAH. (d) Overall survival stratified by Elixhauser comorbidity deciles. Higher comorbidity burden is associated with lower survival from time of PH diagnosis.

Fig. 3.

Effect of PH subtype on risk of death. In a multivariable model, male gender, increasing age at PH diagnosis, and PH due to lung disease, heart disease or multiple causes are each associated with increasing risk of death. Open diamonds indicate reference categories. PH: pulmonary hypertension; PAH: pulmonary arterial hypertension; CTEPH: chronic thromboembolic pulmonary hypertension; CI: confidence interval.

Fig. 4.

Effect of Elixhauser comorbidity categories on outcome of veterans with pulmonary hypertension. A multivariable regression model of the influence of age, gender, race and comorbidities on risk of death from time of PH diagnosis. Increased age and male gender significantly increase risk of death. Notably, weight loss, renal failure, liver disease, and diabetes increase risk of death while obesity is protective. Open diamonds indicate reference categories. PH: pulmonary hypertension; CI: confidence interval.